U.S. patent application number 16/396929 was filed with the patent office on 2019-08-15 for magnetic member for magnetic refrigerator.
This patent application is currently assigned to NGK INSULATORS, LTD.. The applicant listed for this patent is NGK INSULATORS, LTD.. Invention is credited to Yoshio Kikuchi, Yoshimasa Kobayashi.
Application Number | 20190249907 16/396929 |
Document ID | / |
Family ID | 62075990 |
Filed Date | 2019-08-15 |
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United States Patent
Application |
20190249907 |
Kind Code |
A1 |
Kikuchi; Yoshio ; et
al. |
August 15, 2019 |
MAGNETIC MEMBER FOR MAGNETIC REFRIGERATOR
Abstract
A magnetic member for a magnetic refrigerator may include a
tubular outer layer and a wall body having magnetocaloric effect.
The wall body may extend along an axial direction of the outer
layer inside the outer layer and partition an inner space of the
outer layer into a plurality of spaces. The wall body may be
unitary and define a plurality of passages that extend in the axial
direction inside the outer layer.
Inventors: |
Kikuchi; Yoshio;
(Nagoya-Shi, JP) ; Kobayashi; Yoshimasa;
(Nagoya-Shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NGK INSULATORS, LTD. |
Nagoya-Shi |
|
JP |
|
|
Assignee: |
NGK INSULATORS, LTD.
Nagoya-Shi
JP
|
Family ID: |
62075990 |
Appl. No.: |
16/396929 |
Filed: |
April 29, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2017/025816 |
Jul 14, 2017 |
|
|
|
16396929 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C22C 38/005 20130101;
Y02B 30/66 20130101; F25B 2321/002 20130101; F25B 21/00 20130101;
B22F 2302/256 20130101; C22C 2202/02 20130101; B22F 2301/45
20130101; B22F 3/20 20130101; Y02B 30/00 20130101; B22F 3/00
20130101; C22C 38/02 20130101; C22C 19/03 20130101; H01F 1/01
20130101; H01F 1/012 20130101 |
International
Class: |
F25B 21/00 20060101
F25B021/00; H01F 1/01 20060101 H01F001/01 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 2, 2016 |
JP |
2016-215589 |
Claims
1. A magnetic member for a magnetic refrigerator, the magnetic
member comprising: a tubular outer layer; and a wall body having
magnetocaloric effect and porous body, extending along an axial
direction of the outer layer inside the outer layer, partitioning
an inner space of the outer layer into a plurality of spaces and
defining a plurality of passages that extend in the axial direction
inside the outer layer, wherein the wall body surrounding the
plurality of spaces is a unitary wall comprising no joined
surfaces, and the plurality of passages extends from one end of the
magnetic member to another end thereof in the axial direction.
2. The magnetic member according to claim 1, wherein at least one
passage among the plurality of passages includes a sealing body,
and the sealing body is provided at a part of the at least one
passage in the axial direction and blocks a space of the at least
one passage.
3. The magnetic member according to claim 2, wherein the sealing
body is provided at an end of the at least one passage.
4. The magnetic member according to claim 3, wherein the magnetic
member includes a first partial magnetic member and a second
partial magnetic member having a magnetic transition temperature
different from that of the first partial magnetic member, and the
first partial magnetic member and the second partial magnetic
member are joined in the axial direction.
5. The magnetic member according to claim 1, wherein the magnetic
member includes a first partial magnetic member and a second
partial magnetic member having a magnetic transition temperature
different from that of the first partial magnetic member, and the
first partial magnetic member and the second partial magnetic
member are joined in the axial direction.
Description
TECHNICAL FIELD
[0001] This application claims priority to Japanese Patent
Application No. 2016-215589 filed on Nov. 2, 2016, the contents of
which are hereby incorporated by reference into the present
application. The present disclosure relates to a magnetic member
used for a magnetic refrigerator and having magnetocaloric
effect.
BACKGROUND ART
[0002] A magnetic material, of which temperature changes due to
entropy therein being changed by a given magnetic field change, is
known. Then, an AMR (Active Magnetic Regenerative) refrigeration
technology is known which generates a temperature difference
between ends of a container in which a magnetic member constituted
of the above magnetic material is disposed by allowing a heat
transport medium to flow therethrough. Japanese Patent Application
Publication No. 2007-147209 describes examples that a container is
filled with granular magnetic members, that mesh magnetic members
are stacked in the container, and that a honeycomb magnetic member
formed by bending a thin plate into an accordion shape is disposed
in the container, in order to ensure fluidity of a heat transport
medium and heat exchange performance between the heat transport
medium and the magnetic member(s).
SUMMARY OF INVENTION
[0003] Firstly, the AMR refrigeration will be described with
reference to FIGS. 9 and 10. FIG. 9 shows a schematic diagram of a
refrigerator (a heat exchanger) 100 that employs the AMR
refrigeration. A magnetic member 52 is disposed in a container 50.
Ends of the container 50 are respectively provided with openings
50a, 50b through which a heat transport medium flows in and flows
out. FIG. 10 shows temperature distributions in the magnetic member
52. A horizontal axis represents positions of the magnetic member
52 and a vertical axis represents temperatures of the magnetic
member. When a magnetic field is applied to the magnetic member 52,
a temperature of the magnetic member 52 increases overall from a
line 60 to a line 62 as shown in (a). Then, when the heat transport
medium moves from the opening 50b toward the opening 50a in a
direction of an arrow 54, the heat transport medium moves through
the magnetic member 52 while drawing heat from the magnetic member
52. As a result, a temperature difference is generated between an
end portion 52a of the magnetic member 52 and another end portion
52b thereof, as shown by a line 64 in (b). Thereafter, when the
magnetic member 52 is demagnetized, the temperature of the magnetic
member 52 decreases overall with a slope of the line 64 maintained,
as shown by a line 66 in (c). After that, when the heat transport
medium moves from the opening 50a toward the opening 50b in a
direction of an arrow 56, the heat transport medium moves through
the magnetic member 52 while giving heat to the magnetic member 52,
as a result of which the temperature difference between the end
portions 52a and 52b increases as shown by a line 68 in (d). By
repeating a cycle of (a) to (d), the temperature difference between
the end portions 52a and 52b further increases.
[0004] In a refrigerator employing the AMR refrigeration, a large
temperature difference needs to be generated between ends of its
magnetic member. For this reason, it is necessary to facilitate
heat exchange between the magnetic member and a heat transport
medium. The heat exchange between the magnetic member and the heat
transport medium can be facilitated, for example, by increasing a
contact area between the magnetic member and the heat transport
medium and/or by decreasing a traveling speed of the heat transport
medium. However, if the traveling speed of the heat transport
medium is decreased, a temperature gradient is less likely to be
generated in the above-described steps (b), (d), as a result of
which the temperature difference between the ends of the magnetic
member becomes small. Meanwhile, if the contact area between the
magnetic member and the heat transport medium is increased, a
pressure loss is increased generally, and the traveling speed of
the heat transport medium is thereby decreased. As a result, the
temperature difference between the ends of the magnetic member may
become small. To realize a highly effective magnetic refrigerator,
it is necessary to improve a structure of magnetic member. The
disclosure herein aims to provide a novel structure of magnetic
member used in a magnetic refrigerator.
Solution to Technical Problem
[0005] The disclosure herein discloses a magnetic member for a
magnetic refrigerator. The magnetic member may comprise an outer
layer and a unitary wall body. The outer layer may have a tubular
shape. The wall body may have magnetocaloric effect. The wall body
may extend along an axial direction of the outer layer inside the
outer layer, partition an inner space of the outer layer into a
plurality of spaces, and define a plurality of passages that extend
in the axial direction inside the outer layer.
[0006] The above magnetic member can adjust heat exchange
efficiency between the magnetic member and a heat transport medium
by adjusting a porosity ratio inside the outer layer, which is
represented by "(an internal volume of the outer layer--a volume of
the wall body)/(the internal volume of the outer layer)". Further,
the above magnetic member can reduce a pressure loss of the
magnetic member by decreasing a traveling speed of the heat
transport medium by adjusting sizes of the spaces (the passages)
partitioned by the wall body. With the above magnetic member, a
high-performance magnetic refrigerator having a large temperature
gradient can be realized. It should be noted that "unitary wall
body" means that walls defining the spaces are configured in a
unitary structure and that plural components are not joined to one
another to configure the unitary wall body. In other words, there
is no joined surfaces in walls surrounding the spaces.
BRIEF DESCRIPTION OF DRAWINGS
[0007] FIG. 1 shows a perspective view of a magnetic member of a
first embodiment;
[0008] FIG. 2 shows a cross-sectional view along a line II-II in
FIG. 1;
[0009] FIG. 3 shows a cross-sectional view of a refrigerator using
the magnetic member of the first embodiment;
[0010] FIG. 4 shows a cross-sectional view of a magnetic member of
a second embodiment;
[0011] FIG. 5 is a cross-sectional view along a line V-V in FIG.
4;
[0012] FIG. 6 shows a cross-sectional view of a magnetic member of
a third embodiment;
[0013] FIG. 7 shows a cross-sectional view of a magnetic member of
a fourth embodiment;
[0014] FIG. 8 shows an explanatory diagram for a state of particles
constituting a wall body;
[0015] FIG. 9 shows a cross-sectional view of a refrigerator
employing the AMR refrigeration; and
[0016] FIG. 10 shows an explanatory diagram for changes in
temperature of a magnetic member with the AMR refrigeration.
DESCRIPTION OF EMBODIMENTS
[0017] Some of the features characteristic to the technology
disclosed herein will be listed below. It should be noted that the
respective technical elements are independent of one another, and
are useful solely or in combinations.
[0018] A magnetic member disclosed herein may be used in a magnetic
refrigerator. The magnetic refrigerator may comprise a hollow case
and the magnetic member disposed in the hollow case. Openings (a
first opening, a second opening) through which a heat transport
medium flows in and flows out may be provided respectively at ends
of the hollow case. The magnetic member may be disposed between the
first opening and the second opening. The magnetic member may
include a passage through which the heat transport medium moves
from the first opening to the second opening (or from the second
opening to the first opening). The magnetic member may comprise a
tubular outer layer and a wall body disposed in the outer layer.
The wall body may have magnetocaloric effect and extend along an
axial direction of the outer layer inside the outer layer. Further,
the wall body may be unitary, partition an inner space of the outer
layer into a plurality of spaces and define a plurality of passages
that extend in the axial direction inside the outer layer. The heat
transport medium may move through the passages partitioned by the
wall body. Examples of the heat transport medium include water,
alcohols, oils, air and the like.
[0019] As described above, the spaces (the passages) are provided
inside the magnetic member. Further, the wall body itself may be
constituted of a porous body. In this case, there are spaces inside
the wall body as well. To distinguish these spaces, in the
disclosure herein, the spaces partitioned by the wall body (inner
spaces of the outer layer that are devoid of the wall body) are
termed "passages", and the spaces inside the wall body are termed
"voids". Further, a ratio of the "passages" to the inner space of
the outer layer is termed "porosity ratio", and a ratio of the
"voids" inside the wall body is termed "void ratio".
[0020] Various shapes can be adopted for a shape of the magnetic
member (the outer layer) depending on a shape of the hollow case. A
shape of cross section (a cross section perpendicularly
intersecting the axial direction) of the magnetic member may be
circular, ellipsoidal, polygonal, or the like. The outer layer may
have the magnetocaloric effect, or may not have magnetocaloric
effect. The outer layer may be constituted of metal, resin,
ceramic, or a composite material thereof. A thickness of the outer
layer may be 0.3 mm to 5 mm. Further, the porosity ratio of the
magnetic member may be 50% to 90%. With the porosity ratio of 50%
or more, the passages through which the heat transport medium move
can be sufficiently ensured in the magnetic member. Further, with
the porosity ratio of 90% or less, the magnetic member can ensure a
sufficient strength and sufficient heat quantity.
[0021] The wall body may be constituted of a material having the
magnetocaloric effect. Examples of a material having the
magnetocaloric effect include gadolinium (Gd), Gd compounds, La
(Fe, Si).sub.13 compounds, La (Fe, Si).sub.13H compounds, (Mn,
Fe).sub.2(P, Si) compounds, Ni.sub.2MnGa alloys, and the like. The
wall body may be constituted of the above-mentioned substance(s)
only, or may be formed by hardening a mixture of powder (or
particles) of the above-mentioned substance(s) and a bonding
material. Examples of the bonding material include inorganic
binders such as clay, Al.sub.2O.sub.3, SiO.sub.2, glass and silicon
resin; thermosetting resins such as phenol resin; and thermoplastic
resins such as polypropylene (PP). With the wall body that is
formed by hardening the mixture of powder having the magnetocaloric
effect (magnetic body) and the bonding material, heat transmission
in the magnetic member in the axial direction is suppressed because
contact between the magnetic bodies is suppressed, as a result of
which the temperature difference between the ends of the magnetic
member can be maintained to be large. Further, the wall body may
include fibers of cellulose, glass, aluminosilicate and the like to
improve the strength of the wall body.
[0022] The wall body may provide a honeycomb structure in which
passages having a same shape are provided, inside the outer layer.
A shape of cross sections (cross sections perpendicularly
intersecting the axial direction) of the passages may be circular,
ellipsoidal, polygonal, or the like. The wall body may be unitary.
The unitary wall body can be formed, for example, by extrusion
molding.
[0023] A thickness of the wall body may be 50 .mu.m to 1 mm. With
the thickness of the wall body of 50 .mu.m and more, strength of
the passages through which the heat transport medium flows can be
ensured. Further, with the thickness of the wall body of 1 mm or
less, the porosity ratio in the outer layer can be increased and
the contact area between the heat transport medium and the wall
body (magnetic body) can be increased. In some cases, the
passage(s) may be partially blocked to move the heat transport
medium to its adjacent passage(s) through the wall body. In such
cases, the thickness of the wall body may be 500 .mu.m or less to
suppress moving resistance of the heat transport medium.
[0024] The void ratio of the wall body may be 70% or less. In the
case where the heat transport medium is moved to the adjacent
passage(s) through the wall body, the void ratio of the wall body
may be 30% or more. In a case where the heat transport medium is
not moved to the adjacent passage(s), the void ratio of the wall
body may be 70% or less in terms of maintaining the strength of the
wall body.
[0025] The magnetic member may be a combination of plural partial
magnetic members having different magnetic transition temperatures
(Curie temperatures). Specifically, the magnetic member may be a
member in which plural partial magnetic members are joined in the
axial direction. The partial magnetic members may be arranged in
the axial direction in descending order of their magnetic
transition temperatures. That is, the magnetic member may include
at least a first partial magnetic member and a second partial
magnetic member having a magnetic transition temperature different
from that of the first partial magnetic member, and the first
partial magnetic member and the second partial magnetic member may
be joined in the axial direction. When a temperature gradient is
generated in the magnetic member in the axial direction, the
magnetocaloric effect is appropriately yielded in each of the
partial magnetic members. The first partial magnetic member and the
second partial magnetic member may be joined to each other with a
material having a lower thermal conductivity than the wall body.
Due to this, heat is less likely to transfer between the first
partial magnetic member and the second partial magnetic member, and
the temperature gradient in the axial direction can be suppressed
from becoming small.
[0026] At least one passage among the passages surrounded by the
wall body may include a sealing body that blocks a space in the at
least one passage. The sealing body may be provided at a part of
the at least one passage in the axial direction. With the sealing
body, the heat transport medium cannot pass through the at least
one passage from one end to another end thereof, and therefore
moves to its adjacent passage(s) through the wall body while
flowing in the at least one passage. When the heat transport medium
passes through the wall body, greater heat exchange occurs between
the heat transport medium and the wall body (magnetic body). The
sealing body may be provided at an intermediate portion of the at
least one passage, or may be provided at an end of the at least one
passage. Providing the sealing body at the end of the at least one
passage facilitates manufacturing of the magnetic member, as
compared to providing it at the intermediate portion. Further, the
sealing body may be provided at one end of each passage in each of
the above-described first partial magnetic member and second
partial magnetic member. As a result of joining such first partial
magnetic member and second partial magnetic member, some of the
sealing bodies may be provided at intermediate portions of the
passages. A density of the sealing body may be higher than a
density of the wall body. Further, the sealing body may be
constituted of a material having a higher heat capacity than a
material constituting the wall body. Examples of the material of
the sealing body include alumina, stainless steel, resin, glass,
and the like.
EMBODIMENTS
First Embodiment
[0027] A magnetic member 2 and a refrigerator 30 will be described
with reference to FIGS. 1 to 3. As shown in FIGS. 1 and 2, the
magnetic member 2 has a shape of rectangular column and includes an
outer layer 4 and a wall body 6. The wall body 6 extends along an
axial direction of the magnetic member 2 (the outer layer 4) inside
the outer layer 4. The wall body 6 defines a plurality of passages
8. The passages 8 extend from one end of the magnetic member 2 to
another end thereof. That is, the passages 8 are exposed at both
end faces of the magnetic member 2 in the axial direction (FIGS. 1
and 2 show one of the end faces). The magnetic member 2 includes a
honeycomb structure. The magnetic member 2 is manufactured by
extrusion-molding a mixture of La (Fe, Si).sub.13 compound
particles having magnetocaloric effect and glass powder functioning
as an inorganic binder. The outer layer 4 and the wall body 6 are
integrally molded and are constituted of a same material.
[0028] Here, with reference to FIG. 8, particles 6a and an
inorganic binder 6b constituting the wall body 6 (the magnetic
member 2) will be described. As shown in FIG. 8, the particles 6a
are bounded by the inorganic binder 6b. Since the inorganic binder
6b exists between the particles 6a, each one of the particles 6a is
not in contact with another one of the particles 6a. The inorganic
binder 6b is in contact with a part of a surface of each particle
6a and does not cover an entirety of the surface of each particle
6a. In other words, a part of the surface of each particle 6a is
exposed to a void.
[0029] FIG. 3 shows a cross-sectional view of the refrigerator 30
including the magnetic member 2. The refrigerator 30 includes a
container 20 and the magnetic member 2. The magnetic member 2 is
disposed at a center portion 20c of the container 20. A first
opening 20a and a second opening 20b are provided respectively at
both ends of the container 20. A heat transport medium (e.g.,
water) flows in and flows out through the openings 20a, 20b. An
inner diameter of the container 20 continuously increases from each
of its ends (the openings 20a, 20b) toward the center portion 20c.
Therefore, the heat transport medium that has flowed in from the
opening 20a or 20b can move smoothly to the passages 8 located on
an outer side in the magnetic member 2 (passages located in an
outer portion of a cross section perpendicularly intersecting the
axial direction (cross section shown in FIG. 2)). That is, it is
possible to suppress the heat transport medium from concentrating
to the passages 8 located around a center in the magnetic member 2
(passages located in a center portion of the cross section
perpendicularly intersecting the axial direction).
[0030] In the refrigerator 30, the heat transport medium is moved
in a direction of an arrow 54 while the magnetic member 2 is
magnetized, and the heat transport medium is moved in a direction
of an arrow 56 while the magnetic member 2 is demagnetized, for
example. Specifically, the cycle of (a) to (d), which was described
referring to FIGS. 9 and 10, is repeated to generate a temperature
gradient in the magnetic member 2 from a first end 10a to a second
end 10b thereof. The first end 10a comes to have a high temperature
and the second end 10b comes to have a low temperature. The heat
transport medium is moved by a pump (not shown) connected to the
refrigerator 30.
[0031] Advantages of the magnetic member 2 will be described. As
described above, the magnetic member 2 includes the honeycomb
structure in which an inside of the outer layer 4 is partitioned
into a plurality of spaces (the passages 8) by the unitary wall
body 6. The magnetic member 2 with the honeycomb structure can
easily control a structure of flow passages as compared to, for
example, a magnetic member with a structure filled with particles.
Specifically, the magnetic member 2 can ensure the passages 8 that
extend linearly and have a same size from their one ends to their
other ends (see FIG. 3). Further, the magnetic member 2 can control
a porosity ratio (a ratio of the passages with respect to the
magnetic member) and a size of the passages (areas, hydraulic
diameters and the like thereof) by adjusting an arrangement of the
wall body 6. By using the magnetic member 2, a pressure loss in the
refrigerator 30 and heat exchange efficiency between the heat
transport medium and the magnetic member can be accurately
controlled.
[0032] A magnetic member in which a thin plate that was processed
into an accordion shape is rolled and a magnetic member in which
flat plates and accordion-shaped thin plates are stacked are also
referred to as a magnetic member including a honeycomb structure.
Magnetic members including these structures can also ensure
passages that extend linearly from their one ends to their other
ends. However, in these magnetic members, a thickness of the thin
plate (corresponding to a thickness of the wall body 6 of the
magnetic member 2) is restricted due to the processing for the
accordion shape, and a size of the passages is difficult to adjust.
In addition, a material and a void ratio of their wall bodies are
also restricted due to the processing for the accordion shape.
Further, for the honeycomb structure using accordion-shaped thin
plates, the passages are formed by joining the thin plates
together. Since individual thin plates or different portions of the
thin plates are joined together, the plates hit to one another due
to vibrations and the like, by which galling and damage may be
caused. By using the honeycomb structure in which the inside of the
outer layer 4 is partitioned by the unitary wall body 6 as in the
present embodiment, durability can be improved, the thickness of
the wall body and the size of passages can be adjusted, and a large
temperature gradient can be generated between the both ends of the
magnetic member.
[0033] Further, since the particles 6a that constitute the wall
body 6 are not in contact with one another, heat transmission
between the particles 6a is suppressed. Since heat diffusion in an
axial direction of the wall body 6 is suppressed, the temperature
difference between the first end 10a and the second end 10b can be
maintained favorably.
Second Embodiment
[0034] A magnetic member 102 will be described with reference to
FIGS. 4 and 5. The magnetic member 102 can be used in the
refrigerator 30 (see FIG. 3) in place of the magnetic member 2. The
magnetic member 102 is a variant of the magnetic member 2. For
configurations of the magnetic member 102 that are the same as
those of the magnetic member 2, the same reference signs are
assigned and explanation thereof may be omitted.
[0035] In the magnetic member 102, one end of each passage 8 in the
axial direction is blocked by a sealing body 12 or 14.
Specifically, a part of the first end 10a of the magnetic member
102 is blocked by the first sealing bodies 12, and a part of the
second end 10b is blocked by the second sealing bodies 14. As shown
by passages 8a, 8b, the second sealing body 14 is provided in the
passage 8 (the passage 8b) that is adjacent to the passage 8 (the
passage 8a) in which the first sealing body 12 is provided. That
is, the first sealing body 12 is not provided in the passage 8 that
is adjacent to the passage 8 in which the first sealing body 12 is
provided, and the second sealing body 14 is not provided in the
passage 8 that is adjacent to the passage 8 in which the second
sealing body 14 is provided. With the sealing bodies 12, 14
provided, the heat transport medium cannot pass through each of the
passages 8 from one end to the other end thereof, and therefore
moves to its adjacent passage(s) 8 through the wall body 6.
Specifically, the heat transport medium that was supplied from the
first end 10a to the passage 8b moves to its adjacent passages 8a,
8c by passing through an inside of the wall body 6 as shown by the
arrow 56 and then flows out from the second end 10b. Similarly, the
heat transport medium that was supplied from the second end 10b to
the passage 8c moves to its adjacent passages 8b, 8d by passing
through the inside of the wall body 6 as shown by the arrow 54 and
then flows out from the first end 10a. As described above, the wall
body 6 is constituted of the particles 6a and the inorganic binder
6b, and a part of the surface of each particle 6a is exposed to a
void (see FIG. 8). Therefore, when the heat transport medium passes
through the inside of the wall body 6, heat is efficiently
exchanged between the particles 6a (magnetic body) and the heat
transport medium.
[0036] In the magnetic member 102, the heat transport medium moves
from the passage 8 to which it was supplied to its adjacent
passage(s) 8 by passing through the wall body 6 while moving
through the magnetic member 102 (the passage 8) and then flows out
from the passage(s) 8 adjacent to the passage 8 to which it was
supplied. When passing through the wall body 6, the heat transport
medium contacts with the magnetic body constituting the wall body 6
and heat is exchanged effectively therebetween. Although the heat
transport medium does not move linearly in the passages 8 in the
magnetic member 102, it does not constantly move through the wall
body 6. Therefore, the magnetic member 102 can reduce the pressure
loss as compared to a magnetic member filled with particles.
Third Embodiment
[0037] With reference to FIG. 6, a magnetic member 202 will be
described. The magnetic member 202 can also be used in the
refrigerator 30 (see FIG. 3) in place of the magnetic member 2. The
magnetic member 202 is a variant of the magnetic member 102. For
configurations of the magnetic member 202 that are the same as
those of the magnetic member 102, the same reference signs are
assigned and explanation thereof may be omitted.
[0038] The magnetic member 202 includes a first partial magnetic
member 202a, a second partial magnetic member 202b and a third
partial magnetic member 202c, A structure of each of the partial
magnetic members 202a, 202b and 202c is substantially the same as
that of the magnetic member 102. The partial magnetic members 202a,
202b and 202c are constituted of materials having different
magnetic transition temperatures from one another. The first
partial magnetic member 202a including the first end 10a is
constituted of a material having the highest magnetic transition
temperature, and the third partial magnetic member 202c including
the second end 10b is constituted of a material having the lowest
magnetic transition temperature. That is, the magnetic transition
temperatures of the materials become lower from a high-temperature
side (the first end 10a) of the magnetic member 202 toward a
low-temperature side (the second end 10b) thereof.
[0039] The first partial magnetic member 202a and the second
partial magnetic member 202b are connected to each other such that
ends of their passages 8 at which the sealing bodies 12, 14 are not
provided are connected to each other as well as such that the
second sealing bodies 14 of the first partial magnetic member 202a
are in contact with the first sealing bodies 12 of the second
partial magnetic member 202b. Specifically, in the magnetic member
202, the passages 8 of the first partial magnetic member 202a in
which the first sealing bodies 12 are provided are connected to the
passages 8 of the second partial magnetic member 202b in which the
second sealing bodies 14 are provided (the passages 8a, 8c), and
the passages 8 of the first partial magnetic member 202a in which
the second sealing bodies 14 are provided are connected to the
passages of the second partial magnetic member 202b in which the
first sealing bodies 12 are provided (the passages 8b, 8d). The
partial magnetic members 202a, 202b and 202c are connected to one
another with resin. The resin has a lower heat conductivity than
the wall body 6. How the second partial magnetic member 202b and
the third partial magnetic member 202c are connected to each other
is substantially the same as how the first partial magnetic member
202a and the second partial magnetic member 202b are connected to
each other, and thus explanation thereof is omitted.
[0040] In the magnetic member 202, the partial magnetic members
202a, 202b and 202c are connected to each other such that the first
sealing bodies 12 and the second sealing bodies 14 are in contact
with each other. Since the sealing bodies (the sealing bodies 12,
14) are provided at intermediate portions of the passages 8, the
heat transport medium passes through the wall body 6 plural times
(three times, in case of the magnetic member 202) while it moves
from the first end 10a to the second end 10b (or from the second
end 10b to the first end 10a). Due to this, heat exchange
efficiency between the heat transport medium and the magnetic
member 202 can be further improved. Further, since the magnetic
transition temperatures of the materials become higher from the
low-temperature side to the high-temperature side in the magnetic
member 202, heat can be efficiently exchanged in each temperature
region. Further, since the partial magnetic members 202a, 202b and
202c are connected to each other with the material (resin) having a
lower heat conductivity than the material of the wall body 6, heat
can be suppressed from transferring between the first partial
magnetic member 202a and the second partial magnetic member 202b
and between the second partial magnetic member 202b and the third
partial magnetic member 202c. Therefore, the temperature difference
between the first end 10a and the second end 10b can be
maintained.
Fourth Embodiment
[0041] FIG. 7 shows a magnetic member 302. The magnetic member 302
is a variant of the magnetic member 202. For configurations of the
magnetic member 302 that are the same as those of the magnetic
member 202, the same reference signs are assigned and explanation
thereof may be omitted. The magnetic member 302 can also be used in
the refrigerator 30 (see FIG. 3) in place of the magnetic member
2.
[0042] The magnetic member 302 includes a first partial magnetic
member 302a, a second partial magnetic member 302b and a third
partial magnetic member 302c. The partial magnetic members 302a,
302b and 302c have structures that are substantially the same to
each other and their magnetic transition temperatures are
different. The first partial magnetic member 302a is constituted of
a material having the highest magnetic transition temperature and
the third partial magnetic member 302 is constituted of a material
having the lowest magnetic transition temperature. In the magnetic
member 302 as well, the magnetic transition temperatures of the
materials become higher from its low-temperature side toward
high-temperature side.
[0043] In the magnetic member 302, no sealing body is provided in
any of the passages 8. Therefore, in the magnetic member 302, the
heat transport medium moves linearly in each of the passages 8 from
its one end to the other end. That is, in the magnetic member 302,
the heat transport medium does not pass through the wall body 6 to
move to the adjacent passage(s) 8. The magnetic member 302 can
further reduce a pressure loss as compared to the magnetic member
202.
[0044] The above-described second and third embodiments describe
examples that all the passages are provided with the first sealing
body or the second sealing body. However, the magnetic member may
include both the passage in which no sealing body is provided and
the passage in which the first sealing body or the second sealing
body is provided. Further, the third and fourth embodiments
describe examples that one magnetic member is constituted of three
partial magnetic members, however, the number of partial magnetic
members may be two, or may be four or more.
[0045] While specific examples of the present disclosure have been
described above in detail, these examples are merely illustrative
and place no limitation on the scope of the patent claims. The
technology described in the patent claims also encompasses various
changes and modifications to the specific examples described above.
The technical elements explained in the present description or
drawings provide technical utility either independently or through
various combinations. The present disclosure is not limited to the
combinations described at the time the claims are filed. Further,
the purpose of the examples illustrated by the present description
or drawings is to satisfy multiple objectives simultaneously, and
satisfying any one of those objectives gives technical utility to
the present disclosure.
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